Adsorption Equilibrium and Kinetic Characterization of Methylene Blue on Coffee Grounds Activated Carbon

The adsorption characteristics of methylene blue (MB) from aqueous solution on coffee grounds activated carbon (CGAC) were studied.The CGAC was characterized by BET, SEM, TGA and FT-IR techniques.The adsorption capacity of MB on CGAC was greater than that of coffee grounds.The adsorption equilibrium isotherms were well fitted with the Sips equation.The estimated values for the free energy of adsorption (G o ) were -2.90, -3.27, and -3.46kJ/mol at 288, 298 and 308K, which indicated that a spontaneous process.Kinetic studies showed that the adsorption of MB on CGAC in the system followed pseudo-second-order kinetics.